a tip on TypeScript

Author: jlooper

src/chapters/chapter2.md

@@ -114,6 +114,8 @@ This file contains an Angular 2 component, which is the primary building block o
 
 First, you again use TypeScript’s `import` command to bring in externally defined functionality—in this case, the `Component` class from Angular 2 itself. In Angular 2 a component manages a view, or a piece of the user interface that the user sees. A component can be used to define an individual UI element, or an entire page, and eventually we’ll add a bunch of logic to these components and use them to build an entire app. But for now this component is simple for the purpose of demonstration.
 
+> **TIP**: Why [TypeScript](http://www.typescriptlang.org/)? It's strongly recommended that you use TypeScript in your Angular 2 NativeScript app, as it's a first class citizen in both NativeScript and Angular 2. In fact, both NativeScript and Angular 2 were built with TypeScript. The NativeScript CLI makes compiling your TypeScript files seamless, as each time you livesync, run or build the app, the files are recompiled from TypeScript to JavaScript. In some IDEs, such as Visual Studio Code, you might choose to hide the compiled files. A tutorial on how to do this can be found [here](https://code.visualstudio.com/Docs/languages/typescript#_hiding-derived-javascript-files).
+
 Notice the interesting way that the `Component` class is used—with the syntax `@Component`. This is a [TypeScript decorator](https://github.com/Microsoft/TypeScript-Handbook/blob/master/pages/Decorators.md), which allows you to annotate a TypeScript class or method with additional information. For now, you can think of it as a way of adding some metadata configuration to the currently empty `AppComponent` class. Specifically, the `@Component` decorator’s `template` property tells NativeScript how to render this component on the screen. In fact, the `<Label text="hello NativeScript"></Label>` syntax is why you saw “hello NativeScript” when you ran this app earlier.
 
 However, this syntax may look a bit odd if you come from a web development background. On the web, the `<label>` HTML element doesn’t have a `text` attribute, so why do we see it here? Let’s dive into this by looking at how NativeScript UI elements work.